A comprehensive review of the typical and atypical side effects of gabapentin.

BACKGROUND: Gabapentin, a widely prescribed medication for various neuropathic pain conditions, has demonstrated efficacy in managing diverse neurological disorders. While conventional side effects are well-documented, a growing body of evidence suggests the existence of atypical side effects, necessitating comprehensive exploration. This paper aims to systematically review and summarize the literature on the atypical side effects of gabapentin, shedding light on manifestations beyond the conventional spectrum. METHODS: A systematic review was conducted, encompassing peer-reviewed articles published up to the knowledge cutoff date in November 2023. Databases, specifically PubMed, were searched for relevant studies, focusing on atypical side effects such as myoclonus, ataxia, pediatric aggression, respiratory depression, pneumonia, pregnancy complications, sleep interference, encephalopathy, peripheral edema, suicidal ideation, dyskinesia, anorgasmia, and myopathy. Inclusion criteria comprised studies with a focus on gabapentin-related atypical side effects, published in recognized journals and involving human subjects. RESULTS: The review identified a spectrum of atypical side effects associated with gabapentin use, ranging from neurological manifestations like myoclonus and ataxia to behavioral changes such as pediatric aggression and suicidal ideation. Additionally, respiratory complications, pregnancy-related issues, sleep disturbances, and rare complications like encephalopathy and myopathy were observed. Literature synthesis provided insights into the incidence, clinical presentation, and potential mechanisms underlying these atypical side effects. CONCLUSION: This comprehensive review highlights the diverse range of atypical side effects associated with gabapentin use, expanding beyond conventional knowledge. Healthcare practitioners must be cognizant of these manifestations, recognizing their potential impact on patient well-being. As clinical decision-making relies on a thorough understanding of a medication's side effect profile, this review contributes to enhancing awareness and fostering informed practices in the prescription and management of gabapentin. Further research is warranted to elucidate the mechanisms and risk factors associated with these atypical side effects, refining our understanding of gabapentin's safety profile.

Methylene Blue for the Treatment of Radiation-Induced Oral Mucositis during Head and Neck Cancer Treatment: An Uncontrolled Cohort.

Pain from radiation-therapy-induced oral mucositis during head-neck cancer treatment is aggravated by concurrent chemotherapy and commonly fails traditional treatments. To explore safe and sustainable alternatives, we investigated methylene blue oral rinse to reduce radiation-therapy-related oral mucositis pain. For this, we conducted a retrospective observational cohort study in a tertiary-care academic care cancer center including 85 patients with refractory oral mucositis pain during radiation therapy for head-neck cancer. Changes in pain (scale 0-10), oral function burden (scale 0-6) and requirement for percutaneous endoscopic gastrostomy tube placement were measured. Among 58 patients, 60% received radiation therapy alone and 40% received concurrent chemotherapy-radiation therapy. Methylene blue oral rinse (MBOR) significantly decreased oral mucositis pain for at least 6.2 h (median + SD 8 ± 1.68 before vs. 2 ± 2.20 after; p < 0.0001) and oral function burden (3.5 ± 1.33 before vs. 0 ± 0.86 after; p < 0.0001). Eleven patients (19%) had percutaneous endoscopic gastrostomy tubes placed before using methylene blue oral rinse; subsequently, four (36%) resumed oral alimentation after methylene blue oral rinse. Two patients (3%) required percutaneous endoscopic gastrostomy tubes despite methylene blue oral rinse. Minimal adverse events were reported (n = 9, 15%). Our study showed that methylene blue oral rinse was an effective and safe topical treatment for opioid-refractory oral pain from oral mucositis associated with radiation therapy for head-neck cancer.

Impact Of COVID-19 Pandemic and Updated Utilization Patterns of Sacroiliac Joint Injections from 2000 to 2020 in The Fee-For-Service (FFS) Medicare Population.

BACKGROUND: Among the multiple causes of low back and lower extremity pain, sacroiliac joint pain has shown to be prevalent in 10% to 25% of patients with persistent axial low back pain without disc herniation, discogenic pain, or radiculitis. Over the years, multiple Current Procedural Terminology (CPT) codes have evolved with the inclusion of intraarticular injections, nerve blocks, and radiofrequency neurotomy, in addition to percutaneous sacroiliac joint fusions. Previous assessments of utilization patterns of sacroiliac joint interventions only included sacroiliac joint intraarticular injections, since the data was not available prior to the introduction of new codes. A recent assessment revealed an increase of 11.3%, and an annual increase of 1.2% per 100,000 Medicare population from 2009 to 2018, showing a decline in growth patterns. During the past 2 years, the COVID-19 pandemic has also had significant effects on the utilization patterns of sacroiliac joint interventions. STUDY DESIGN: The impact of the COVID-19 pandemic and analysis of growth patterns of sacroiliac joint interventions (intraarticular injections, nerve blocks, radiofrequency neurotomy, arthrodesis and fusion) was evaluated from 2010 to 2019 and 2010 to 2020, with a comparative analysis from 2019 to 2020 to assess the impact of the COVID-19 pandemic. OBJECTIVES: To update utilization patterns of sacroiliac joint interventions with assessment of the impact of the COVID-19 pandemic. METHODS: The Centers for Medicare and Medicaid Services (CMS) Physician/Supplier Procedure Summary (PSPS) Master dataset was utilized in the present analysis. RESULTS: The results of this evaluation demonstrated a significant impact of the COVID-19 pandemic with a 19.2% decrease of utilization of sacroiliac joint intraarticular injections from 2019 to 2020. There was a 23.3% increase in sacroiliac joint arthrodesis and a 5.3% decrease for sacroiliac joint fusions with small numbers from 2019 to 2020. However, data was not available for sacroiliac joint nerve blocks and sacroiliac joint radiofrequency neurotomy as these codes were incorporated in 2020. Overall, from 2010 to 2019, sacroiliac joint intraarticular injections showed an annual increase of 0.9% per 100,000 Medicare population. Sacroiliac joint arthrodesis and fusion showed an annual increase from 2010 to 2020 per 100,000 Medicare population of 29% for arthrodesis and 13.3% for fusion. LIMITATIONS: Limitations of this study include a lack of inclusion of Medicare Advantage patients constituting approximately 30% to 40% of the overall Medicare population. As with all claims-based data analyses, this study is retrospective and thus potentially limited by bias. Finally, patients who are non-Medicare are not part of the dataset. CONCLUSIONS: The study shows the impact of the COVID-19 pandemic with a significant decrease of intraarticular injections of 19.2% from 2019 to 2020 per 100,000 Medicare population. These decreases of intraarticular injections are accompanied by a 5.3% decrease of fusion, but a 23.3% increase of arthrodesis from 2019 to 2020 per 100,000 Medicare population. Overall, the results showed an annual increase of 0.9% per 100,000 Medicare population for intraarticular injections, a 35.4% annual increase for sacroiliac joint arthrodesis and an increase of 15.5% for sacroiliac joint fusion from 2010 to 2019.

Impact of Ketamine on Opioid Use and Persistent Pain After Cytoreductive Surgery with Hyperthermic Chemotherapy.

BACKGROUND: Persistent pain and opioid use can be devastating after cytoreductive surgery (CRS) and hyperthermic intraoperative chemotherapy (HIPEC). METHODS: We conducted a retrospective study to investigate the impact of ketamine use on postoperative complications and persistent and chronic pain after CRS-HIPEC. RESULTS: Ketamine reduced perioperative opioid use before and after implementation of recovery after surgery programs. Ketamine did not impact the formation of persistent and chronic pain formation and long-term opioid use. Postoperative complications and postoperative re-operations were independent predictors of persistent pain. Interestingly, the risk of having a complication was increased by 1% for every doubling in opioids used intraoperatively. CONCLUSION: Ketamine use reduces perioperative opioid consumption in patients undergoing CRS-HIPEC, but it is not associated with improvements in long-term opioid use and chronic pain.

Percutaneous Cordotomy for Pain Palliation in Advanced Cancer: A Randomized Clinical Trial Study Protocol.

BACKGROUND: Cancer pain, one of the most common symptoms for patients with advanced cancer, is often refractory to maximal medical therapy. A controlled clinical trial is needed to provide definitive evidence to support the use of ablative procedures such as cordotomy for patients with medically refractory cancer pain. OBJECTIVE: To assess the efficacy of cordotomy for patients with unilateral advanced cancer pain using a controlled clinical trial study design. The secondary objectives are to define the patient experience of cordotomy for medically refractory cancer pain as well as to determine the utility of magnetic resonance imaging as a non-invasive biomarker for successful cordotomy. METHODS: We will undertake a single-institution, double-blind, sham-controlled clinical trial of cordotomy in patients with refractory cancer pain. Patients in the cordotomy arm will undergo a percutaneous computed tomography-guided cordotomy at C1-C2, while patients in the control arm will undergo a similar procedure where the needle will not penetrate the thecal sac. The primary endpoint will be the reduction in pain intensity, as measured by the Edmonton Symptoms Assessment Scale. EXPECTED OUTCOMES: We expect that patients randomized to cordotomy will have a significantly greater reduction in pain intensity than those patients randomized to the control surgical intervention. DISCUSSION: This randomized clinical trial comparing cordotomy with a control intervention will provide the level of evidence necessary to determine whether cordotomy should be the standard of care intervention for patients with advanced cancer pain.

Efficacy of Superior Hypogastric Plexus Neurolysis for the Treatment of Cancer-Related Pelvic Pain.

OBJECTIVE: Cancer-related abdominal and pelvic pain syndromes can be debilitating and difficult to treat. The objective of this study was to evaluate the efficacy of superior hypogastric plexus blockade or neurolysis (SHPN) for the treatment of cancer-related pelvic pain. DESIGN: Retrospective study. SETTING: MD Anderson Cancer Center, Houston, Texas. METHODS: We enrolled 46 patients with cancer-related pelvic pain who underwent SHPN. A numeric rating scale (NRS) was used for pain intensity, and symptom burden was evaluated using the Edmonton Symptom Assessment System at baseline, visit 1 (within one month), and visit 2 (within one to six months). RESULTS: Forty-six patients who received SHPN showed a significant reduction in pain score from 6.9 to 5.6 at visit 1 (P = 0.01). Thirty of the 46 patients continued to complete visit 2 follow-up, and the NRS score was consistently lower at 4.5 at visit 2 (P < 0.0001), with anxiety and appetite improved significantly. There was no significant change in the morphine equivalent dose at visits 1 and 2. The efficacy of the block was not influenced by patients' age, gender, type of cancer, cancer stage, regimen of chemotherapy and/or radiation therapy, diagnostic block, approach or laterality of procedure, or type or amount of neurolytic agent. Nonsmokers with high baseline pain scores were more likely to have improved treatment outcomes from SHPN at short-term follow-up. Adverse effects with SHPN were mild and well tolerated. CONCLUSIONS: SHPN was an effective and relatively safe procedure for pain associated with pelvic malignancies. There is a need for larger prospective trials.

Minimally Invasive Cordotomy for Refractory Cancer Pain: A Randomized Controlled Trial.

BACKGROUND: Up to 30% of patients with cancer continue to suffer from pain despite aggressive supportive care. The present study aimed to determine whether cordotomy can improve cancer pain refractory to interdisciplinary palliative care. MATERIALS AND METHODS: In this randomized controlled trial, we recruited patients with refractory unilateral somatic pain, defined as a pain intensity (PI) ≥4, after more than three palliative care evaluations. Patients were randomized to percutaneous computed tomography-guided cordotomy or continued interdisciplinary palliative care. The primary outcome was 33% improvement in PI at 1 week after cordotomy or study enrollment as measured by the Edmonton Symptom Assessment Scale. RESULTS: Sixteen patients were enrolled (nine female, median age 58 years). Six of seven patients (85.7%) randomized to cordotomy experienced >33% reduction in PI (median preprocedure PI = 7, range 6-10; 1 week after cordotomy median PI = 1, range 0-6; p = .022). Zero of nine patients randomized to palliative care achieved a 33% reduction in PI. Seven patients (77.8%) randomized to palliative care elected to undergo cordotomy after 1 week. All of these patients experienced >33% reduction in PI (median preprocedure PI = 8, range 4-10; 1 week after cordotomy median PI = 0, range 0-1; p = .022). No patients were withdrawn from the study because of adverse effects of the intervention. CONCLUSION: These data support the use of cordotomy for pain refractory to optimal palliative care. The findings of this study justify a large-scale randomized controlled trial of percutaneous cordotomy. IMPLICATIONS FOR PRACTICE: This prospective clinical trial was designed to determine the improvement in pain intensity in patients randomized to either undergo cordotomy or comprehensive palliative care for medically refractory cancer pain. This study shows that cordotomy is effective in reducing pain for medically refractory cancer pain, and these results can be used to design a large-scale comparative randomized controlled trial that could provide the evidence needed to include cordotomy as a treatment modality in the guidelines for cancer pain management.

Limited Midline Myelotomy for Intractable Visceral Pain: Surgical Techniques and Outcomes.

BACKGROUND: Limited midline myelotomy targets the midline nociceptive pathway for intractable visceral pain. Multiple techniques are available for limited midline myelotomy; however, outcome data for each technique are sparse. OBJECTIVE: To review our experience with open and percutaneous approaches for limited midline myelotomy for intractable visceral pain. METHODS: Patients who underwent limited midline myelotomy for intractable visceral pain were reviewed. Myelotomy was performed using 3 techniques: open limited myelotomy, percutaneous radiofrequency myelotomy, and percutaneous mechanical myelotomy. Demographic and perioperative clinical data were recorded. In addition to the visual analog scale and Karnofsy performance score, outcomes were categorized as excellent (no pain), good (considerable reduction in pain, not requiring opioids stronger than codeine), fair (minimal reduction in pain, but no change in opioid medication requirement), and poor (no reduction in pain). RESULTS: Eight patients (median age 56.5 yr, 6 females) underwent limited myelotomy. Four patients underwent open limited thoracic myelotomy with excellent pain outcomes. Three patients underwent percutaneous radiofrequency lesioning with fair (n = 1) and poor outcomes (n = 2). One patient underwent percutaneous mechanical lesioning with a good outcome (n = 1). The median duration of follow-up was 11 wk (2-54 wk). Two patients reported minor sensory complications after the procedure. CONCLUSION: In our preliminary experience, outcomes for open limited thoracic myelotomy were superior to percutaneous approaches. Given the limited utilization of this technique, multicenter registries are needed to further evaluate the best surgical technique for limited midline myelotomy.

Compliance with Opioid Therapy: Distinguishing Clinical Characteristics and Demographics Among Patients with Cancer Pain.

Background: Because an increase of patients who misuse opioids has been identified in our cancer clinical setting through urine drug testing (UDT) and the Screener and Opioid Assessment for Patient's with Pain-Short Form (SOAPP-SF), we conducted this retrospective cohort study to identify patient characteristics that are associated with UDT that indicates noncompliance. Methods: Over a two-year period, 167 of 8,727 patients (2.4%) seen in the pain clinic and who underwent UDT were evaluated to determine compliance with prescribed opioid regimens. Descriptive clinical and demographic data were collected, and group differences based on compliance with opioid therapy were evaluated. Results: Fifty-eight percent of the patients were noncompliant with their prescribed opioid therapy. Noncompliant patients were younger than compliant patients, with a median age of 46 vs 49 years (P = 0.0408). Noncompliant patients were more likely to have higher morphine equivalent daily doses; however, the difference was not statistically significant. Patients with a history of alcohol (ETOH) (P = 0.0332), illicit drug use (P = 0.1014), and smoking (P = 0.4184) were more likely noncompliant. Univariate regression analysis showed that a history of ETOH use (P = 0.034), a history of anxiety (P = 0.027), younger age (P = 0.07), and a SOAPP-SF score of 4 or higher (P = 0.05) were associated with an abnormal UDT. Conclusions: History of ETOH use, anxiety, high SOAPP-SF score, and younger age were associated with UDT that indicates noncompliance. Given the very small percentage of UDT testing, it is quite likely that a significant number of patients who did not undergo UDT were also nonadherent with treatment recommendations.

Responsible, Safe, and Effective Prescription of Opioids for Chronic Non-Cancer Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines.

BACKGROUND: Opioid use, abuse, and adverse consequences, including death, have escalated at an alarming rate since the 1990s. In an attempt to control opioid abuse, numerous regulations and guidelines for responsible opioid prescribing have been developed by various organizations. However, the US opioid epidemic is continuing and drug dose deaths tripled during 1999 to 2015. Recent data show a continuing increase in deaths due to natural and semisynthetic opioids, a decline in methadone deaths, and an explosive increase in the rates of deaths involving other opioids, specifically heroin and illicit synthetic fentanyl. Contrary to scientific evidence of efficacy and negative recommendations, a significant proportion of physicians and patients (92%) believe that opioids reduce pain and a smaller proportion (57%) report better quality of life. In preparation of the current guidelines, we have focused on the means to reduce the abuse and diversion of opioids without jeopardizing access for those patients suffering from non-cancer pain who have an appropriate medical indication for opioid use. OBJECTIVES: To provide guidance for the prescription of opioids for the management of chronic non-cancer pain, to develop a consistent philosophy among the many diverse groups with an interest in opioid use as to how appropriately prescribe opioids, to improve the treatment of chronic non-cancer pain and to reduce the likelihood of drug abuse and diversion. These guidelines are intended to provide a systematic and standardized approach to this complex and difficult arena of practice, while recognizing that every clinical situation is unique. METHODS: The methodology utilized included the development of objectives and key questions. The methodology also utilized trustworthy standards, appropriate disclosures of conflicts of interest, as well as a panel of experts from various specialties and groups. The literature pertaining to opioid use, abuse, effectiveness, and adverse consequences was reviewed, with a best evidence synthesis of the available literature, and utilized grading for recommendation as described by the Agency for Healthcare Research and Quality (AHRQ).Summary of Recommendations:i. Initial Steps of Opioid Therapy 1. Comprehensive assessment and documentation. (Evidence: Level I; Strength of Recommendation: Strong) 2. Screening for opioid abuse to identify opioid abusers. (Evidence: Level II-III; Strength of Recommendation: Moderate) 3. Utilization of prescription drug monitoring programs (PDMPs). (Evidence: Level I-II; Strength of Recommendation: Moderate to strong) 4. Utilization of urine drug testing (UDT). (Evidence: Level II; Strength of Recommendation: Moderate) 5. Establish appropriate physical diagnosis and psychological diagnosis if available. (Evidence: Level I; Strength of Recommendation: Strong) 6. Consider appropriate imaging, physical diagnosis, and psychological status to collaborate with subjective complaints. (Evidence: Level III; Strength of Recommendation: Moderate) 7. Establish medical necessity based on average moderate to severe (≥ 4 on a scale of 0 - 10) pain and/or disability. (Evidence: Level II; Strength of Recommendation: Moderate) 8. Stratify patients based on risk. (Evidence: Level I-II; Strength of Recommendation: Moderate) 9. Establish treatment goals of opioid therapy with regard to pain relief and improvement in function. (Evidence: Level I-II; Strength of Recommendation: Moderate) 10. Obtain a robust opioid agreement, which is followed by all parties. (Evidence: Level III; Strength of Recommendation: Moderate)ii. Assessment of Effectiveness of Long-Term Opioid Therapy 11. Initiate opioid therapy with low dose, short-acting drugs, with appropriate monitoring. (Evidence: Level II; Strength of Recommendation: Moderate) 12. Consider up to 40 morphine milligram equivalent (MME) as low dose, 41 to 90 MME as a moderate dose, and greater than 91 MME as high dose. (Evidence: Level II; Strength of Recommendation: Moderate) 13. Avoid long-acting opioids for the initiation of opioid therapy. (Evidence: Level I; Strength of Recommendation: Strong) 14. Recommend methadone only for use after failure of other opioid therapy and only by clinicians with specific training in its risks and uses, within FDA recommended doses. (Evidence: Level I; Strength of Recommendation: Strong) 15. Understand and educate the patients of the effectiveness and adverse consequences. (Evidence: Level I; Strength of Recommendation: Strong) 16. Similar effectiveness for long-acting and short-acting opioids with increased adverse consequences of long-acting opioids. (Evidence: Level I-II; Strength of recommendation: Moderate to strong) 17. Periodically assess pain relief and/or functional status improvement of ≥ 30% without adverse consequences. (Evidence: Level II; Strength of recommendation: Moderate) 18. Recommend long-acting or high dose opioids only in specific circumstances with severe intractable pain. (Evidence: Level I; Strength of Recommendation: Strong)iii. Monitoring for Adherence and Side Effects 19. Monitor for adherence, abuse, and noncompliance by UDT and PDMPs. (Evidence: Level I-II; Strength of Recommendation: Moderate to strong) 20. Monitor patients on methadone with an electrocardiogram periodically. (Evidence: Level I; Strength of Recommendation: Strong). 21. Monitor for side effects including constipation and manage them appropriately, including discontinuation of opioids when indicated. (Evidence: Level I; Strength of Recommendation: Strong)iv. Final Phase 22. May continue with monitoring with continued medical necessity, with appropriate outcomes. (Evidence: Level I-II; Strength of Recommendation: Moderate) 23. Discontinue opioid therapy for lack of response, adverse consequences, and abuse with rehabilitation. (Evidence: Level III; Strength of Recommendation: Moderate) CONCLUSIONS: These guidelines were developed based on comprehensive review of the literature, consensus among the panelists, in consonance with patient preferences, shared decision-making, and practice patterns with limited evidence, based on randomized controlled trials (RCTs) to improve pain and function in chronic non-cancer pain on a long-term basis. Consequently, chronic opioid therapy should be provided only to patients with proven medical necessity and stability with improvement in pain and function, independently or in conjunction with other modalities of treatments in low doses with appropriate adherence monitoring and understanding of adverse events.Key words: Chronic pain, persistent pain, non-cancer pain, controlled substances, substance abuse, prescription drug abuse, dependency, opioids, prescription monitoring, drug testing, adherence monitoring, diversionDisclaimer: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."

Effectiveness of Splanchnic Nerve Neurolysis for Targeting Location of Cancer Pain: Using the Pain Drawing as an Outcome Variable.

The effectiveness of splanchnic nerve neurolysis (SNN) for cancer-related abdominal pain has been investigated using numeric pain intensity rating as an outcome variable. The outcome variable in this study used the grid method for obtaining a targeted pain drawing score on 60 patients with pain from pancreatic or gastro-intestinal primary cancers or metastatic disease to the abdominal region. Results demonstrate excellent inter-rater agreement (intra-class correlation [ICC] coefficient at pre-SNN = 0.97 and ICC at within one month post-SNN = 0.98) for the grid method of scoring the pain drawing and demonstrate psychometric generalizability among patients with cancer-related pain. Using the Wilcoxon signed rank test and associated effect sizes, results show significant improvement in dispersion of pain following SNN. Effect sizes for the difference in pre-SNN to 2 post-SNN time points were higher for the pain drawing than for pain intensity rating. Specifically, the effect size difference from pre- to within one month post-SNN was r = 0.42 for pain drawing versus r = 0.23 for pain intensity rating. Based on a smaller subset of patients who were seen within 1 - 6 months following SNN, the effect size difference from pre-SNN was r = 0.46 for pain drawing versus r = 0.00 for pain intensity rating. Collectively, these data support the use of the pain drawing as a reliable outcome measure among patients with cancer pain for procedures such as SNN that target specific location and dispersion of pain.

The Effectiveness of Alcohol Versus Phenol Based Splanchnic Nerve Neurolysis for the Treatment of Intra-Abdominal Cancer Pain.

UNLABELLED: Pancreatic and other upper abdominal organ malignancies can produce intense visceral pain syndromes that are frequently treated with splanchnic nerve neurolysis (SNN) or celiac plexus neurolysis (CPN). Although commonly performed with either alcohol or phenol, there is scant literature on the comparative effectiveness, duration of benefit, and complication profile comparing the 2 agents. This study presents a retrospective chart review of 93 patients who underwent SNN for cancer-related abdominal pain in order to describe patient characteristics, examine comparative efficacy, duration of benefit, and incidence of complications with alcohol vs. those of phenol. Consistent with previous studies, SNN reduced reported pain scores while not significantly reducing opioid consumption. No difference in pain outcomes was found comparing alcohol versus phenol based neurolytic techniques. Celiac axis tumor infiltration and pre-procedural local radiation therapy did not change the effectiveness of the procedure. Our data demonstrated that 44.57% of patients had = 30% pain reduction while 43.54% did not have pain reduction. Interestingly, the procedure produced significant improvements in anxiety, depression, difficulty thinking clearly, and feeling of well-being. In addition, no difference in complications was seen between the agents either. SNN was an effective and relatively safe procedure for the treatment of pain associated with pancreatic and other upper abdominal organ malignancies in our sample of patients. Choice of neurolytic agent can appropriately be left to the clinical judgment and local availability of the treating physician. The change in ancillary symptoms has a theoretical basis that supports a biopsychosocial model of pain since changes in one target area (pain) impact other related ones (depression and anxiety). KEY WORDS: Celiac plexus, splanchnic nerves, neurolysis, nerve block, alcohol, ethanol, phenol, pain, cancer pain, abdominal pain, visceral pain, symptom assessment.

Lumbar subarachnoid hematoma following an epidural blood patch for meningeal puncture headache related to the implantation of an intrathecal drug delivery system.

Persistent meningeal puncture headache (MPH) is a known complication following both intentional and unintentional puncture of the dura mater.  We present a case of persistent MPH following implantation of an intrathecal drug delivery system (IDDS). Two separate epidural blood patches (EBP) were performed under radiographic guidance with contrast visualization of the epidural space on postoperative days 16 and 28, respectively. The case was complicated by the development of a symptomatic lumbar subarachnoid hematoma diagnosed on postoperative day 35. The patient subsequently underwent a laminectomy, evacuation of the hematoma, and explanation of the IDDS. This case illustrates a potential unique morbidity associated with the EBP in a patient with an IDDS. The report concludes with a brief review of MPH followed by a discussion of possible mechanisms underlying this complication.

Risk stratification of opioid misuse among patients with cancer pain using the SOAPP-SF.

BACKGROUND: Opioids are recognized as an integral part of the armamentarium in the management of cancer pain. There has been a growing awareness of the misuse of prescription opioids among cancer patients. More research is needed to detail risk factors and incidence for opioid misuse among cancer pain patients. METHODS: We reviewed 522 patient charts that were seen in our Pain Center from January 1, 2009 to June 30, 2009 for risk stratification of opioid misuse with demographic and clinical factors utilizing the Screener and Opioid Assessment for Patients with Pain-short form (SOAPP-SF). Group differences based on High (≥4) and Low (<4) SOAPP-SF scores were evaluated at initial visit, follow-up within a month and 6-9 months. RESULTS: One hundred forty-nine of the 522 (29%) patients had a SOAPP-SF score of ≥4. The mean age for patients with high SOAPP-SF score (≥4) was 50 ± 14 vs 56 ± 14 for patients with low SOAPP-SF score (<4) (P < 0.0001). The pain scores were higher for patients with high SOAPP-SF score compared with patients with low SOAPP-SF score at consult (P < 0.0001). Morphine equivalent daily dose (MEDD) was higher for patients with high SOAPP-SF score compared with patients with low SOAPP-SF score at consult (P = 0.0461). Fatigue, feeling of well-being, and poor appetite were higher among the high SOAPP-SF group at initial visit (P < 0.0001, <0.0001, <0.0149, respectively). The high SOAPP-SF score patients also had statistically significant (P < 0.05) higher anxiety and depression scores at all three time points. In the multivariate analysis, patients younger than 55 years have a higher odds of having a "high" SOAPP-SF score than patients 55 years and older {odds ratio (OR) (95% confidence interval [CI]) = 2.76 (1.58, 4.81), P = 0.0003} adjusting for employment status, disease status, treatment status, usual pain score, and morphine equivalency at consult. Patients with higher usual pain score at consult have higher odds of a "high" SOAPP-SF score (OR [95% CI] = 1.34 [1.19, 1.51], P < 0.0001) adjusting for age, employment status, disease status, treatment status, and morphine equivalency at consult. CONCLUSION: Patients classified by the SOAPP-SF in the current study as high risk tended to be younger, endorse more pain, have higher MEDD requirement, and endorse more symptoms of depression and anxiety. These findings are consistent with the literature on risk factors of opioid abuse in chronic pain patients which suggests that certain patient characteristics such as younger age, anxiety, and depression symptomatology are associated with greater risk for opioid misuse. However, a limitation of the current study is that other measures of opioid abuse were not available for validation and comparison with the SOAPP-SF.

Infectious complications related to intrathecal drug delivery system and spinal cord stimulator system implantations at a comprehensive cancer pain center.

BACKGROUND: Intrathecal drug delivery (IDD) and spinal cord stimulator (SCS) systems are implantable devices for the management of both chronic and cancer pain. Although these therapies have favorable long-term outcomes, they are associated with occasional complications including infection. The incidence of infectious complications varies from 2 - 8% and frequently requires prolonged antibiotics and device revision or removal. Cancer patients are particularly susceptible to infectious complications because they are immunocompromised, malnourished, and receiving cytotoxic cancer-related therapies. OBJECTIVE: Determine if cancer pain patients have a higher incidence of infectious complications following implantation of IDD or SCS systems than non-cancer pain patients. STUDY DESIGN: Retrospective chart review. SETTING: Single tertiary comprehensive cancer hospital. METHODS: Following local Institutional Review Board (IRB) approval, we collected data on infectious complications for IDD and SCS systems implanted at MD Anderson Cancer Center for the treatment of cancer and chronic pain. The examined implants were performed from July 15, 2006, to July 14, 2009. In addition, we obtained data regarding patient comorbidities and perioperative risk factors to assess their impact on infectious complications. RESULTS: One hundred forty-two devices were implanted in 131 patients during the examined period. Eighty-three of the devices were IDD systems and 59 were SCS systems. Eighty percent of the patients had a diagnosis of cancer. Four infectious complications were noted with an overall infectious risk of 2.8%. The infection rate was 2.4% for IDD systems versus 3.4% for SCS systems (P = 1). All infections were at the implantable pulse generator (IPG) or pump pocket site. The rate of infection was 2.7% for cancer patients and 3.3% for non-cancer patients (P = 1). Neither the perioperative administration of prophylactic antibiotics (P = 0.4) nor the National Nosocomial Infection Surveillance (NNIS) risk level for individual patients (P = 0.15) were statistically associated with infectious complication. The mean surgical time was longer for cases with infection at 215 ± 93 minutes versus 132 ± 52 minutes for those without infection which was statistically significant (P = 0.02). LIMITATIONS: The major limitation of this study is that it was a retrospective analysis. An additional limitation is that 51(38.9%) of our patients either died or were lost to follow-up during the year following implantation which may have led to an underestimation of our infection rates. CONCLUSIONS: The experience of this tertiary cancer pain center demonstrates that infectious complications following implantation of IDD and SCS systems are relatively rare events in cancer patients. Contrary to our initial hypothesis, no difference was found in the infection rate between cancer and non-cancer patients. The main factor associated with increased risk of infectious complications was increased surgical time, indicating a need to minimize patient time in the operating room. The low infectious complication rate seen in this series compared to previous reports in non-cancer patients is likely multifactorial in nature.

Distinguishing features of cancer patients who smoke: pain, symptom burden, and risk for opioid misuse.

UNLABELLED: Although many cancer patients who have pain are smokers, the extent of their symptom burden and risk for opioid misuse are not well understood. In this study we analyzed records of patients being treated for cancer pain, 94 of whom were smokers and 392 of whom were nonsmokers, to determine smoking status group differences. Smokers had significantly higher pain intensity, fatigue, depression, and anxiety than nonsmokers (independent samples t-tests P < .002). Smokers were at higher risk for opioid misuse based on the short form of the Screener and Opioid Assessment for Patients with Pain (SOAPP). Specifically, smokers had more frequent problems with mood swings, taking medications other than how they are prescribed, a history of illegal drug use, and a history of legal problems (chi-square tests P ≤ .002). Changes in pain and opioid use were examined in a subset of patients (146 nonsmokers and 46 smokers) who were receiving opioid therapy on at least 2 of the 3 data time points (consult, follow-up 1 month after consult, follow-up 6 to 9 months after consult). Results based on multilevel linear modeling showed that over a period of approximately 6 months, smokers continued to report significantly higher pain than nonsmokers. Both smokers and nonsmokers reported a significant decline in pain across the 6-month period; the rate of decline did not differ across smokers and nonsmokers. No significant difference over time was found in opioid use between smokers and nonsmokers. These findings will guide subsequent studies and inform clinical practice, particularly the relevancy of smoking cessation. PERSPECTIVE: This article describes pain, symptom burden, and risk for opioid misuse among cancer patients with pain across smoking status. Smoking appears to be a potential mechanism for having an increased pain and symptom burden and risk for opioid misuse. This improved understanding of cancer pain will inform clinical practice.

American Society of Interventional Pain Physicians (ASIPP) guidelines for responsible opioid prescribing in chronic non-cancer pain: Part I--evidence assessment.

BACKGROUND: Opioid abuse has continued to increase at an alarming rate since the 1990 s. As documented by different medical specialties, medical boards, advocacy groups, and the Drug Enforcement Administration, available evidence suggests a wide variance in chronic opioid therapy of 90 days or longer in chronic non-cancer pain. Part 1 describes evidence assessment. OBJECTIVES: The objectives of opioid guidelines as issued by the American Society of Interventional Pain Physicians (ASIPP) are to provide guidance for the use of opioids for the treatment of chronic non-cancer pain, to produce consistency in the application of an opioid philosophy among the many diverse groups involved, to improve the treatment of chronic non-cancer pain, and to reduce the incidence of abuse and drug diversion. The focus of these guidelines is to curtail the abuse of opioids without jeopardizing non-cancer pain management with opioids. RESULTS: 1) There is good evidence that non-medical use of opioids is extensive; one-third of chronic pain patients may not use prescribed opioids as prescribed or may abuse them, and illicit drug use is significantly higher in these patients. 2) There is good evidence that opioid prescriptions are increasing rapidly, as the majority of prescriptions are from non-pain physicians, many patients are on long-acting opioids, and many patients are provided with combinations of long-acting and short-acting opioids. 3) There is good evidence that the increased supply of opioids, use of high dose opioids, doctor shoppers, and patients with multiple comorbid factors contribute to the majority of the fatalities. 4) There is fair evidence that long-acting opioids and a combination of long-acting and short-acting opioids contribute to increasing fatalities and that even low-doses of 40 mg or 50 mg of daily morphine equivalent doses may be responsible for emergency room admissions with overdoses and deaths. 5) There is good evidence that approximately 60% of fatalities originate from opioids prescribed within the guidelines, with approximately 40% of fatalities occurring in 10% of drug abusers. 6) The short-term effectiveness of opioids is fair, whereas the long-term effectiveness of opioids is limited due to a lack of long-term (> 3 months) high quality studies, with fair evidence with no significant difference between long-acting and short-acting opioids. 7) Among the individual drugs, most opioids have fair evidence for short-term and limited evidence for long-term due to a lack of quality studies. 8) The evidence for the effectiveness and safety of chronic opioid therapy in the elderly for chronic non-cancer pain is fair for short-term and limited for long-term due to lack of high quality studies; limited in children and adolescents and patients with comorbid psychological disorders due to lack of quality studies; and the evidence is poor in pregnant women. 9) There is limited evidence for reliability and accuracy of screening tests for opioid abuse due to lack of high quality studies. 10) There is fair evidence to support the identification of patients who are non-compliant or abusing prescription drugs or illicit drugs through urine drug testing and prescription drug monitoring programs, both of which can reduce prescription drug abuse or doctor shopping. DISCLAIMER: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."

American Society of Interventional Pain Physicians (ASIPP) guidelines for responsible opioid prescribing in chronic non-cancer pain: Part 2--guidance.

RESULTS: Part 2 of the guidelines on responsible opioid prescribing provides the following recommendations for initiating and maintaining chronic opioid therapy of 90 days or longer. 1. A) Comprehensive assessment and documentation is recommended before initiating opioid therapy, including documentation of comprehensive history, general medical condition, psychosocial history, psychiatric status, and substance use history. ( EVIDENCE: good) B) Despite limited evidence for reliability and accuracy, screening for opioid use is recommended, as it will identify opioid abusers and reduce opioid abuse. ( EVIDENCE: limited) C) Prescription monitoring programs must be implemented, as they provide data on patterns of prescription usage, reduce prescription drug abuse or doctor shopping. ( EVIDENCE: good to fair) D) Urine drug testing (UDT) must be implemented from initiation along with subsequent adherence monitoring to decrease prescription drug abuse or illicit drug use when patients are in chronic pain management therapy. ( EVIDENCE: good) 2. A) Establish appropriate physical diagnosis and psychological diagnosis if available prior to initiating opioid therapy. ( EVIDENCE: good) B) Caution must be exercised in ordering various imaging and other evaluations, interpretation and communication with the patient, to avoid increased fear, activity restriction, requests for increased opioids, and maladaptive behaviors. ( EVIDENCE: good) C) Stratify patients into one of the 3 risk categories - low, medium, or high risk. D) A pain management consultation, may assist non-pain physicians, if high-dose opioid therapy is utilized. ( EVIDENCE: fair) 3. Essential to establish medical necessity prior to initiation or maintenance of opioid therapy. ( EVIDENCE: good) 4. Establish treatment goals of opioid therapy with regard to pain relief and improvement in function. ( EVIDENCE: good) 5. A) Long-acting opioids in high doses are recommended only in specific circumstances with severe intractable pain that is not amenable to short-acting or moderate doses of long-acting opioids, as there is no significant difference between long-acting and short-acting opioids for their effectiveness or adverse effects. ( EVIDENCE: fair) B) The relative and absolute contraindications to opioid use in chronic non-cancer pain must be evaluated including respiratory instability, acute psychiatric instability, uncontrolled suicide risk, active or history of alcohol or substance abuse, confirmed allergy to opioid agents, coadministration of drugs capable of inducing life-limiting drug interaction, concomitant use of benzodiazepines, active diversion of controlled substances, and concomitant use of heavy doses of central nervous system depressants. ( EVIDENCE: fair to limited) 6. A robust agreement which is followed by all parties is essential in initiating and maintaining opioid therapy as such agreements reduce overuse, misuse, abuse, and diversion. ( EVIDENCE: fair) 7. A) Once medical necessity is established, opioid therapy may be initiated with low doses and short-acting drugs with appropriate monitoring to provide effective relief and avoid side effects. ( EVIDENCE: fair for short-term effectiveness, limited for long-term effectiveness) B) Up to 40 mg of morphine equivalent is considered as low dose, 41 to 90 mg of morphine equivalent as a moderate dose, and greater than 91 mg of morphine equivalence as high dose. ( EVIDENCE: fair) C) In reference to long-acting opioids, titration must be carried out with caution and overdose and misuse must be avoided. ( EVIDENCE: good) 8. A) Methadone is recommended for use in late stages after failure of other opioid therapy and only by clinicians with specific training in the risks and uses. ( EVIDENCE: limited) B) Monitoring recommendation for methadone prescription is that an electrocardiogram should be obtained prior to initiation, at 30 days and yearly thereafter. ( EVIDENCE: fair) 9. In order to reduce prescription drug abuse and doctor shopping, adherence monitoring by UDT and PMDPs provide evidence that is essential to the identification of those patients who are non-compliant or abusing prescription drugs or illicit drugs. ( EVIDENCE: fair) 10. Constipation must be closely monitored and a bowel regimen be initiated as soon as deemed necessary. ( EVIDENCE: good) 11. Chronic opioid therapy may be continued, with continuous adherence monitoring, in well-selected populations, in conjunction with or after failure of other modalities of treatments with improvement in physical and functional status and minimal adverse effects. ( EVIDENCE: fair). DISCLAIMER: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."